The picture shows
the scheme of a J-Pole antenna. The high impedance feeding point of a
lambda/2-wire
(L1) is matched from some KOhms to a low impedance with a
lambda/4-
matching sector (L2).

The point XX has an impedance of
50 Ohm
for direct feed with a coax cable. XX is symmetrical, a choke or
balun could be useful to avoid sleeve waves on the screen of the coax.

A
very simple method for the lambda/4-part
is to use a 450-Ohm-Wireman cable.

I have built up
the antenna for 2 m, 6 m, 12 m and 30 m. The table gives the values for
experimenting with the other bands.

L1=0,471
lambda
(Halfwave-Radiator) L2=0,223 lambda (Wireman-cable)

Solder
the braid of the 50-Ohm-coax at the right X, the inner conductor to the left X.
XX about 5-10% of L2.

The antenna can be mounted in several ways:

The classic J-Pole with both sections mounted vertically.

Length 3/4-lambda,
only for the higher bands.

It is no difference in the radiating conditions, if the
lambda/4-part
is vertical or horizontal.

The pattern is identical with a
vertical dipole.

Both parts horizontally mounted

The "Zepp"-configuration

The antennas were tested on 2 m, 6 m, 1 2m and 30 m. The lengths for the bands
marked with "*" have not been tested, try with he given dimensions.
For other frequencies use the following formula for insulated 2-mm-wires for L1.
Not-insulated wires need a longer L1-section.

The
points X-X are 5-10% from the shorted part of the Wireman-cable (look for best
SWR).